Dissertations / Theses: 'Synchrotron'

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Botez, Cristian E. "Synchrotron x-ray scattering studies of metallic surfaces /." free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3052151.

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Pearson, Martin. "Synchrotron infrared microspectroscopy." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324753.

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Crosbie, Jeffrey. "Synchrotron microbeam radiation therapy." Monash University. Faculty of Science. School of Physics, 2008. http://arrow.monash.edu.au/hdl/1959.1/64948.

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This thesis presents interdisciplinary, collaborative research in the field of synchrotron microbeam radiation therapy (MRT). Synchrotron MRT is an experimental radiotherapy technique under consideration for clinical use, following demonstration of efficacy in tumour-bearing rodent models with remarkable sparing of normal tissue. A high flux, X-ray beam from a synchrotron is segmented into micro-planar arrays of narrow beams, typically 25 μm wide and with peak-to-peak separations of 200 μm. The radiobiological effect of MRT and the underlying cellular mechanisms are poorly understood. The ratio between dose in the ‘peaks’of the microbeams to the dose in the ‘valleys’, between the microbeams, has strong biological significance. However, there are difficulties in accurately measuring the dose distribution for MRT. The aim of this thesis is to address elements of both the dosimetric and radiobiological gaps that exist in the field of synchrotron MRT. A method of film dosimetry and microdensitometry was adapted in order to measure the peak-to-valley dose ratios for synchrotron MRT. Two types of radiochromic film were irradiated in a phantom and also flush against a microbeam collimator on beamline BL28B2 at the SPring-8 synchrotron. The HD-810 and EBT varieties of radiochromic film were used to record peak dose and valley dose respectively. In other experiments, a dose build-up effect was investigated and the half value layer of the beam with and without the microbeam collimator was measured to investigate the effect of the collimator on the beam quality. The valley dose obtained for films placed flush against the collimator was approximately 0.25% of the peak dose. Within the water phantom, the valley dose had increased to between 0.7–1.8% of the peak dose, depending on the depth in the phantom. We also demonstrated, experimentally and by Monte Carlo simulation, that the dose is not maximal on the surface and that there is a dose build-up effect. The microbeam collimator did not make an appreciable difference to the beam quality. The measured values of peak-to-valley dose ratio were higher than those predicted by previously published Monte Carlo simulation papers. For the radiobiological studies, planar (560 Gy) or cross-planar (2 x 280 Gy or 2 x 560 Gy) irradiations were delivered to mice inoculated with mammary tumours in their leg, on beamline BL28B2 at the SPring-8 synchrotron. Immunohistochemical staining for DNA double strand breaks, proliferation and apoptosis was performed on irradiated tissue sections. The MRT response was compared to conventional radiotherapy at 11, 22 or 44 Gy. The results of the study provides the first evidence for a differential tissue response at a cellular level between normal and tumour tissues following synchrotron MRT. Within 24 hours of MRT to tumour, obvious cell migration had occurred into and out of irradiated zones. MRT-irradiated tumours showed significantly less proliferative capacity by 24 hours post-irradiation (P = 0.002). Median survival times for EMT-6.5 and 67NR tumour-bearing mice following MRT (2 x 560 Gy) and conventional radiotherapy (22 Gy) increased significantly compared to unirradiated controls (P < 0.0005). However, there was markedly less normal tissue damage from MRT than from conventional radiotherapy. MRT-treated normal skin mounts a more coordinated repair response than tumours. Cell-cell communication of death signals from directly irradiated, migrating cells, may explain why tumours are less resistant to high dose MRT than normal tissue.

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Gayadeen, Sandira. "Synchrotron electron beam control." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:234025b3-2d1b-495e-846e-688f14149b21.

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This thesis develops techniques for the design and analysis of controllers to achieve sub-micron accuracy on the position of electron beams for the optimal performance of synchrotrons. The techniques have been applied to Diamond Light Source, the UK's national synchrotron facility. Electron beam motion in synchrotrons is considered as a large-scale, two-dimensional process and by using basis functions, controllable modes of the process are identified which are independent and allow the design to be approached in terms of a family of single-input, single-output transfer functions. This thesis develops techniques for the design and analysis of controllers to achieve sub-micron accuracy on the position of electron beams for the optimal performance of synchrotrons. The techniques have been applied to Diamond Light Source, the UK's national synchrotron facility. Electron beam motion in synchrotrons is considered as a large-scale, two-dimensional process and by using basis functions, controllable modes of the process are identified which are independent and allow the design to be approached in terms of a family of single-input, single-output transfer functions. In this thesis, loop shaping concepts for dynamical systems are applied to the two-dimensional frequency domain to meet closed loop specifications. Spatial uncertainties are modelled by complex Fourier matrices and the closed loop robust stability, in the presence of spatial uncertainties is analysed within an Integral Quadratic Constraint framework. Two extensions to the unconstrained, single-actuator array controller design are considered. The first being anti-windup augmentation to give satisfactory performance when rate limit constraints are imposed on the actuators and the second being a strategy to account for two arrays of actuators with different dynamics. The resulting control schemes offer both stability and performance guarantees within structures that are feasible for online computation in real time.

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Pennicard, David. "3D detectors for synchrotron applications." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/694/.

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3D detectors are a novel variety of photodiode radiation detector, invented by Parker, Kenney and Segal (1997). Instead of having n- and p-type contacts on the front and back surfaces of a silicon substrate, like a standard photodiode, they have columns of doped material passing through the thickness of the silicon. This structure means that the detector can combine a reasonable substrate thickness with a very small electrode spacing, resulting in a low depletion voltage, fast charge collection and low charge sharing. These detectors have a couple of promising applications. Their fast charge collection and low depletion voltage should make them very radiation-tolerant. So, they could be used for future particle physics experiments at the Super Large Hadron Collider (SLHC), where high levels of radiation damage are expected. Also, their low charge sharing means they could potentially improve X-ray diffraction measurements at synchrotrons such as Diamond Light Source. This would allow these experiments, for example, to determine the structures of biological molecules more accurately. However, before 3D devices can be used in practical experiments, their design and fabrication must be optimised to ensure that reliable, high-performance detectors can be produced on a reasonably large scale. The aim of this thesis is to evaluate and understand the behaviour of a variety of 3D detectors using a combination of lab tests and computer simulations. Using these results, future fabrication runs can then be re-designed to improve their performance. Firstly, the "Synopsys TCAD" simulation package was used to determine the optimum design for 3D detectors at the SLHC. It was found that the device behaviour depends strongly on the electrode spacing, and the choice of spacing requires a trade-off between different effects. Using a smaller spacing reduces the detector's operating voltage, and improves the charge collection efficiency by reducing carrier trapping. However, reducing the spacing also increases the capacitance, resulting in greater noise, and also increases the insensitive volume occupied by the columns. At SLHC radiation damage levels, the optimal electrode spacing was found to be 40-55 micrometres. CNM (Centro Nacional de Microelectronica) in Barcelona have produced a set of "double sided" 3D detectors. The n- and p-type columns in these devices are etched from opposite sides of the substrate and do not pass through the full substrate thickness. Computer simulations show that these detectors should give similar performance to full-3D detectors. The main difference is that these devices have slower charge collection around their front and back surfaces. Basic electrical characterisation of the detectors showed that they have low depletion voltages. However, the guard ring current varied a great deal between detectors, though this was fixed by using better guard structures. Charge collection tests on these detectors using beta particles gave mixed results. A heavily-irradiated detector gave a relatively high collection signal, similar to the simulated value, which demonstrated the structure's radiation hardness. However, an unirradiated detector gave an unexpectedly low collection signal. This was perhaps due to poor coupling between this detector and the readout chip. Three of these "double-sided" 3D detectors were bonded to Medipix2 pixel readout chips. These chips are specifically designed for X-ray detection, and can count individual photon hits. The detectors worked successfully, and initial lab tests demonstrated that they depleted extremely rapidly. The detectors were then tested in an X-ray beam at Diamond Light Source. These tests showed that the detectors have lower charge sharing than a standard planar photodiode. For example, 24% of the hits on a double-sided 3D detector at 22V were shared, compared to 40% on a planar detector at 100V. A set of devices with a simplified "single-type-column" structure, fabricated by FBK-IRST in Trento, were also tested. Simulations showed that although this structure will have a low depletion voltage and fast electron collection, the hole collection will be slow. This will result in poorer behaviour than full- and double-sided 3D detectors. This was confirmed by lab tests, which showed that when the detector was coupled to fast readout electronics, the charge collection efficiency was reduced due to ballistic deficit.

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Baine, Michael. "Laser undulated synchrotron radiation sources /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2000. http://wwwlib.umi.com/cr/ucsd/fullcit?p9956463.

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Botteon, Andrea. "Synchrotron emission and astrophysical applications." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/5626/.

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Cheng, Yin [Verfasser], and Ingo [Akademischer Betreuer] Krossing. "In situ synchrotron radiation computed laminography for materials failure analysis = In-situ Synchrotron-Laminographie für Materialfehleranalyse." Freiburg : Universität, 2013. http://d-nb.info/1123479097/34.

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Krishnamurthy, Satheesh. "Synchrotron radiation studies of nanostructured materials." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430334.

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Nichols, Anthony Peter. "Synchrotron studies of X-ray detectors." Thesis, University of Leicester, 1996. http://hdl.handle.net/2381/35749.

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This thesis is an account of research into various aspects of X-ray detection, with a common thread being the use of synchrotron radiation. An investigation into the so called "X-ray vectorial effect" is described. The aim being to design a detector able to determine the degree of polarisation in astronomical X-ray sources and the angle of the polarisation vector. Two experiments are reported, the first showing marked polarisation sensitivity, but not totally answering doubts. The second experiment demonstrated that the X-ray vectorial effect does not exist and with it the critical importance of accurate calibration of angles of incidence. Monte Carlo modelling of electron transport in photocathodes resulting from X-ray absorption is presented alongside compatible experimental results. An alternative polarimetry technique, also based on utilising the known polarisation sensitivity of photoelectron creation, is then derived and predicted to be competitive with the best current polarimeters and offering greater scope for improvement. A novel efficiency calibration technique for bare Microchannel plates (MCPs) using the Daresbury synchrotron with very low beam current is examined allowing us to conduct photon counting measurements, while utilising the energy tunability of the synchrotron. In quantum efficiency measurements this technique brought out absorption edge fine structure and EXAFS from the constituents of MCP lead glass with the energy resolution required in calibration the MCP spectrometer readout on the AXAF satellite. Complimentary measurements of the quantum efficiency of alkali halide (Csl and KBr) photocathodes are presented over the continuous energy range between 2 and 8 keV and at a range of incidence angles. These alkali halides are generally coated onto the MCP channels to enhance the detector efficiency. Synchrotron radiation was also utilised to examine the radiation damage characteristics of alkali halide photocathodes. Both Csl and KBr are shown to suffer significant degradation of photoelectric efficiency after minutes of irradiation with of order 1010 photons s-1. The way X-ray flux, angle of incidence and energy affect the degree of degradation is investigated. A solid state model of lattice defect production, diffusion and trapping incorporating surface effects and photoelectron emission is described. This first attempt at modelling the physical basis of photoyield degradation is shown to accurately recreate much of the observed behaviour including the shapes of the signal decay curves and recovery out of the synchrotron beam yielding a clear insight into the degradation process and suggesting ways its effects can be reduced.

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PANACCIONE, GIANCARLO. "Magnetometrie de surface en rayonnement synchrotron." Paris 6, 1995. http://www.theses.fr/1995PA066686.

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La spectroscopie de photoemission en rayonnement synchrotron a ete utilisee pour des experiences de magnetisme de surface, au moyen de la mesure de la polarisation des electrons secondaires (sp) et de la photoemission en geometrie chirale ; nous avons analyse si et sous quelles conditions le dichroisme magnetique lineaire en geometrie chirale, ou lmdad, peut devenir une magnetometrie de surface et d'interface. Nous avons etudie les proprietes magnetiques de la surface du fer en presence de la segregation de soufre. Les variations relatives du moment magnetique des atomes de fer de surface ont ete determinees pour ce systeme

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Stewart, Graeme Douglas. "Silicon pixel detectors for synchrotron applications." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4384/.

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Recent advances in particle accelerators have increased the demands being placed on detectors. Novel detector designs are being implemented in many different areas including, for example, high luminosity experiments at the LHC or at next generation synchrotrons. The purpose of this thesis was to characterise some of these novel detectors. The first of the new detector types is called a 3D detector. This design was first proposed by Parker, Kenney and Segal (1997). In this design, doped electrodes are created that extend through the silicon substrate. When compared to a traditional photodiode with electrodes on the opposing surfaces, the 3D design can combine a reasonable detector thickness with a small electrode spacing resulting in fast charge collection and limited charge sharing. The small electrode spacing leads to the detectors having lower depletion voltages. This, combined with the fast collection time, makes 3D detectors a candidate for radiation hard applications. These applications include the upgrades to the Large Hadron Collider (LHC) leading to the High Luminosity Large Hadron Collider (HL-LHC). The limited charge sharing of the devices can also improve their performance when being employed as imaging sensors. This will provide benefits in X-ray diffraction experiments. The first experiment to evaluate the 3D detector design analysed for this thesis involved utilising a telescope consisting of 6 calibrated detector planes and a beam of pions from the Super Proton Synchrotron (SPS) at CERN. Once the tracks through the telescope were reconstructed, these gave predicted hits on the 3D detector that could be compared to the recorded energy depositions. By making this comparison, a measure of the detector’s efficiency in various regions of the pixels was made. The overall efficieny of the pixel was measured at 93.0±0.5%. The detector was also rotated with respect to the incident beam, increasing the efficiency to 99.8±0.5% for an angle of 10◦, and the detector bias was altered to measure the effect of over-depletion. Measurements of the charge sharing and resolution properties of the device were also reported. Another detector design that was investigated was a slim edge detector. Instead of the typical guard ring structures that a normal device would employ, this detector reduced the size of these structures to enable easier tiling of the detectors. This was done by scanning the reduced edge and the standard edge of the detector with an X-ray beam with a width FWHM of 7 μm and 15 keV. The noise level of the strip closest to the cleaved edge was twice as large as that of the adjacent strip with no degradation of the charge collection capacity. The next experiment to evaluate a short, double sided 3D strip detector was a Transient Current Technique (TCT) experiment. The TCT technique allows the electric field in the 3D devices to be probed in a way not possible before. The TCT technique uses the current waveform produced by the detector in response to a near delta function point laser pulse (illumination). The waveforms are recorded as a function of illumination position over the surface of the device under test as a function of detector bias. This data gives information on the portion of the induced signal from electron or hole motion. From the rise times of the signals the velocity profile of the carriers in the devices and therefore electric fields can be determined. The collected charge was calculated from the integral of the waveforms. The detectors were tested prior to irradiation, after irradiating to a dose of 5 x 10^15 1MeV equivalent neutrons/cm^2, and after periods of annealing at elevated temperatures. Annealing was achieved in situ by warming to 60 ◦C for 20 to 600 minutes corresponding to room temperature annealing of between 8 and 200 days. Before irradiation, full lateral depletion between the columns occurs at low bias voltages, at approximately 3 V. A uniform carrier velocity between the columns is not achieved until the bias is equal to 40 V. Both the drift of electrons and holes provide equal contributions to the measured signals. After irradiation there is clear charge multiplication enhancement along the line between columns with a very non-uniform velocity profile in the unit cell of the device. In addition, charge trapping greatly suppresses the contribution of the holes on the signal produced. The final novel detector type was an Active Pixel Sensor (APS). Recent developments in CMOS fabrication processes have allowed new sensors to be developed and tailor-made for specific applications. These challenge traditional Charge Coupled Devices (CCD) in some areas. The characterisation of the APS device took place in an X-ray diffraction experiment at the Diamond Light Source where it was evaluated alongside a CCD. The camera gain and stability had been determined prior to the experiment taking place. During the experiment, the dark current, noise, signal to noise and image lag performance was evaluated and compared between the APS and the CCD. The signal to noise of the APS and the CCD was comparable (150 and 200 respectively) when the same integration time was used.

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Margaritondo, Giorgio, and Johann Rafelski. "The relativistic foundations of synchrotron radiation." INT UNION CRYSTALLOGRAPHY, 2017. http://hdl.handle.net/10150/625068.

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Special relativity (SR) determines the properties of synchrotron radiation, but the corresponding mechanisms are frequently misunderstood. Time dilation is often invoked among the causes, whereas its role would violate the principles of SR. Here it is shown that the correct explanation of the synchrotron radiation properties is provided by a combination of the Doppler shift, not dependent on time dilation effects, contrary to a common belief, and of the Lorentz transformation into the particle reference frame of the electromagnetic field of the emission-inducing device, also with no contribution from time dilation. Concluding, the reader is reminded that much, if not all, of our argument has been available since the inception of SR, a research discipline of its own standing.

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Salomon, Felix. "Refraction index modification by synchrotron radiation." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-44255.

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Ludwig, Wolfgang. "Development and Applications of Synchrotron Radiation Microtomography." Diss., lmu, 2001. http://nbn-resolving.de/urn:nbn:de:bvb:19-3447.

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Weaver, Jill Suzanne. "Synchrotron Radiation Studies of Magnetic Thin Films." Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485147.

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The purpose of these studies has been to gain a better understanding of the relationships that govern the interfaces of ferromagnetic / ill-V semiconductor heterostructures and other materials. The results here in are expected to promote the development of next generation spin electronic devices which may open the way toward incorporating data processing and storage in a single device through the utilisation of both electron charge and spin. Development ofsuch devices relies a great deal on the quality ofinterface which can be set up between the semiconductor and ferromagnetic structures, as a poor interface leads to difficulty in carrier transport between the materials. Studies into interface magnetism, which can most effectively be carried out using the synchrotron technique of x-ray magnetic circular dichroism (XMCD), have been used to make substantial strides forward in the understanding of the importance of interface quality. It is hoped that these shidies involving synchrotron radiation, predominantly in the area of XMCD, wiJI help the further development ofnew spintronic technologies.

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Ballard, Keith Richard. "Particle acceleration and synchrotron emission in blazars." Thesis, University of Edinburgh, 1991. http://hdl.handle.net/1842/26210.

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An optical and infrared observing programme which provides the most detailed information yet available for blazars is described. From this it is possible to make progress in understanding the physical processes which are occurring on the smallest scales within the emission region. Later theoretical calculations including a treatment of synchrotron emission incorporating losses and a realistic source geometry are presented together with a model of particle acceleration at relativistic shocks in disordered magnetic fields. The work contained in this thesis can explain the radiation and make predictions regarding future observations. The conclusion is that the observations support the idea that the synchrotron emitting electrons are being accelerated at a collisionless shock front in a disordered field.

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Thompson, Stephen P. "Studies of cosmic dusts using synchrotron radiation." Thesis, Keele University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303876.

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Wright, Andrew Edward. "Studies of reactive intermediates with synchrotron radiation." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242644.

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Martis, V. "Synchrotron radiation studies of multicomponent metal oxides." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1388216/.

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The work described in this thesis is focused on the development of characterization methods for determining the structure of multicomponent metal oxides using synchrotron radiation techniques, in particular, X-ray Absorption Fine Structure (XAFS) and Energy Resolved Electron Yield X-ray Absorption Spectroscopy (EREY– XAS). XAFS is a superior technique for determining the local structure of, for example, transition metals that are used as dopants in very low concentrations. It also provides information on early stages of crystallization processes before a material develops sufficient long range order. Energy resolved XAS was developed as an alternative to conventional transmission and fluorescence techniques which probe mainly the bulk of materials. This techniques yield information about the local structure from the near surface region of materials. The other complementary techniques used for characterization of materials were XRD, Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). New insights about formation of Bi2MoO6 crystallites from an amorphous gel below 200oC were obtained with a novel in situ setup, in which XAFS and XRD was combined with RAMAN spectroscopy in a single experiment. Combined XRD/XAFS technique was used for determining the growth mechanism of Bi2MoO6 formed under hydrothermal conditions from an amorphous gel. The reaction kinetics was quantified by using the Avrami-Erofe’ev formalism. The surface sensitive of EREY–XAS was performed on several materials in particular chromium doped Fe2O3 catalysts and cobalt substituted aluminophosphates such as CoAlPO-18 and CoAlPO-34. The sensitivity of technique was assessed by comparison with conventional XAS techniques and XPS. Finally, the interactions of a synchrotron X-ray beam with a sample were studied. In particular, the effects of exposure to a monochromatic 10 keV X-ray beam on thermally induced crystallization of lithium disilicate glass were investigated.

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Liu, Wenqing. "Synchrotron radiation studies of spintronic hybrid systems." Thesis, University of York, 2014. http://etheses.whiterose.ac.uk/8180/.

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Spintronics is an emergent interdisciplinary topic for the studies of spin-based, other than or in addition to charge-only-based physical phenomena, which promises not only new capabilities of electronic devices, but also abundant science. For applied materials, the spin ordering has long been investigated within the context of conventional ferromagnetic materials (FMs), while the study of spin generation, relaxation, and spin-orbit coupling (SOC) in semiconductors (SCs) took off only recently with the advent of spintronics and it is here that many novel materials and FM/SC hybrid structures can find their greatest potential in both science and technology. In the pursuit for such goals, the intrinsic material properties are important indicators and the artificially synthetized hybrid systems (layered FM/SC structures and FM-doped SCs) are valuable models for studying spindependent phenomena and could potentially be used as actual components for an eventual spintronic device. These results are expected to contribute to some of the most fundamental questions of the contemporary spintronic materials research, such as the FM/SC interfacial hybridization and magnetism, the spin and orbital ordering of ferrites, and the fundamental magnetism of doped TIs, and the proximity effects in FM/DMS and FM/doped TI heterostructures.

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Treacy, Jon. "Synchrotron studies of TiO2 single crystal surfaces." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/synchrotron-studies-of-tio2-single-crystal-surfaces(4c8a0ee8-b2b8-460c-a174-b4478256d4e7).html.

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Titanium dioxide (TiO2) is an abundant, inexpensive and non-toxic material that is most commonly used as a white pigment in paints. Since the discovery by Fujishima and Honda in 1972 that water splits into hydrogen and oxygen gas at the surface of TiO2 on exposure to sunlight, there has been a massive research effort into understanding and improving the photoactivity of TiO2. One aspect of this is the characterisation of so-called ‘model’ surfaces, i.e. very large single crystal faces with low levels of contamination at ultra high vacuum (UHV) pressures, allowing the study of a single structure with a minimum of unknown variables effecting experimental results. Two techniques that are used to probe surface structure, amongst many, are Surface X-ray Diffraction (SXRD) and Photoelectron Spectroscopy (PES). SXRD allows quantitative determination of surface structure with high precision, and PES reveals surface chemical composition. In the context of this thesis both of these techniques were exploited at synchrotron radiation sources, which produce light of high brightness. In addition, the development of routines for extraction of SXRD data from 2D detectors to allow SXRD analysis is described. SXRD is employed to probe the structure of anatase-TiO2(101) both in UHV and following immersion in water vapour. The optimum UHV structure is largely in agreement with that previously predicted computationally, although there are some discrepancies in terms of atomic displacements. Water immersion leads to a H2O/OH terminated surface. The surface structure of a rutile-TiO2(110)(1x1) surface, that had been prepared under non-UHV conditions, using a wet chemical preparation technique, is also determined with SXRD. The studied surface, which was highly hydrophilic, has a similar substrate termination to UHV-prepared rutile-TiO2(110)(1x1) but with adsorbed surface H2O/OH species. Finally, PES is used to gain insight into the O1s signature of surface bridging oxygens on rutile-TiO2(110), as well as those (if any) of oxygen adatoms. Concerning bridging oxygens, it is demonstrated that there is no discernable shift in the O1s core level for these atoms away from the bulk oxide peak. Regarding oxygen adatoms, no conclusive evidence of a distinct emission signal in the O1s core level or valence band spectra can be discerned, due to interference from carbon contamination.

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Peng, Chengyuan. "Diagnosis of Steatosis, Precancerous Lesions and Hepatocellular Carcinoma Using Infrared Microspectroscopy." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA11T032.

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Carcinome hépatocellulaire (CHC) est le sixième cancer et la deuxième cause de mortalité par cancer dans le monde. Dans la majorité des cas, le CHC se développe sur une maladie chronique associée à des étiologies variées telles que l'infection par le virus de l'hépatite B ou l’hépatite C, la consommation excessive d'alcool et des maladies métaboliques. Le développement des maladies chroniques du foie qui conduisent à la cirrhose puis au cancer induisent des modifications de la composition chimique des cellules et des tissus. En effet, la carcinogenèse hépatique est un processus en plusieurs étapes caractérisé par la progression de nodules de régénération, de nodules dysplasiques de bas grade puis de grade et enfin du CHC. Le traitement du CHC reste difficile et la transplantation du foie est la seule option thérapeutique curative à long terme. Le problème est qu'il n'y a pas de marqueur objectifs et quantifiables pour contrôler la qualité d’un greffon. Des biomarqueurs spécifiques marquant la progression du CHC font également défauts.Dans ce travail de thèse, nous avons évalué l’intérêt de la microspectroscopie infrarouge (IR) pour le diagnostic de la stéatose, qui est le facteur le plus important affectant la reprise de la fonction hépatique après greffe de foie. La microspectroscopie infrarouge permet de détecter de façon qualitative et quantitative les caractéristiques biochimiques liées aux différents constituants moléculaires présents dans l'échantillon biologique. Nos travaux ont montré que la progression de la stéatose hépatique correspond non seulement à l'accumulation de lipides, mais également à des changements spectaculaires dans la composition qualitative du tissu. En effet, le bas grade de stéatose présente une diminution de la teneur en glycogène et une augmentation concomitante de lipides par rapport au foie normal. La stéatose intermédiaire montre une augmentation de glycogène et des changements majeurs sont observés en ce qui concerne les lipides, avec une contribution significative des acides gras estérifiés, des chaînes de carbone allongées et des lipides insaturés. Ces caractéristiques sont encore plus prononcées dans les hauts degrés de stéatose. De plus, nous avons mis en évidence que des changements biochimiques majeurs se produisent dans la partie non-stéatosique du tissu malgré son aspect normal sur le plan histologique, ce qui suggère que l’organe dans son ensemble reflète le degré de la stéatose.La deuxième partie de la thèse est focalisée la carcinogenèse hépatique. Il s’agit d’un processus en plusieurs étapes qui se caractérise dans la plupart des foies cirrhotiques par la progression de nodules hyperplasiques de régénération vers des lésions précancéreuses telles que les nodules dysplasiques de bas grade puis de haut grade et enfin le CHC. Le diagnostic différentiel entre nodules dysplasiques en particulier de haut garde et CHC reste extrêmement difficile. Nous avons abordé le potentiel de la microspectroscopie IR pour le diagnostic des nodules cirrhotiques. Nous avons observé de profondes modifications de la composition biochimique du foie pathologique. En effet, des changements importants ont été détectés dans la composition des lipides, des protéines et des sucres mettant en évidence la reprogrammation métabolique dans la carcinogenèse. Les principaux changements ont été observés dans le domaine de fréquence 950-1480 cm-1 dans lequel plusieurs bandes permettaient la discrimination des nodules cirrhotiques, dysplasiques et tumoraux. Enfin, nous avons montré que le diagnostic peut être réalisé à l’aide d’un microscope de laboratoire qui peut être facilement mis en œuvre en milieu hospitalier
Hepatocellular carcinoma (HCC) is the sixth most common neoplasm and the second most common cause of death in the world. Hepatocarcinogenesis is a multistep process characterized in patients with chronic liver diseases by a spectrum of hepatic nodules that mark the progression from regenerative nodules to dysplastic lesions followed by HCC. Liver transplantation remains the curative therapeutic option able to treat both the HCC and the underlying liver disease. The issue is that there is no objective and quantifiable marker for quality control of liver graft. Specific biomarkers of early stages of HCC are also an unmet need.In this study, we have evaluated the potential of infrared (IR) microspectroscopy for the diagnosis of steatosis, one of the most important factors affecting the liver allograft function. Vibrational microspectroscopy, such as Fourier transform infrared microspectroscopy (FTIR), allows detecting spectral characteristics associated with different molecular components present in the biological sample, both qualitatively and quantitatively. Our first working hypothesis was that the progression of liver steatosis corresponds not only to the accumulation of lipids but also to dramatic changes in the qualitative composition of tissue. Indeed, a lower grade of steatosis showed a decrease in glycogen content and concomitant increase in lipids in comparison with normal liver. Intermediate steatosis exhibited an increase in glycogen and major changes in lipids, with a significant contribution of esterified fatty acids with elongated carbon chains and unsaturated lipids, and these features were more pronounced in a high grade of steatosis. Furthermore, we have shown, that FTIR approach allows a systemic discrimination of morphological features, leading to a separate investigation of steatotic vesicles and the non-steatotic counterpart of the tissue. This highlighted the fact that dramatic biochemical changes occur in the non-steatotic part of the tissue also despite its normal histological aspect, suggesting that the whole tissue reflects the grade of steatosis. The second part of the thesis focused on hepatocarcinogenesis; a multistep process that is characterized in most cirrhotic livers by the progression from hyperplastic regenerative nodules to low grade dysplastic nodules (LGDN), high grade dysplastic nodules (HGDN) and finally small HCC which corresponds either to vaguely nodular well differentiated HCC so called early HCC or to distinctly nodular moderately differentiated hepatocellular carcinomas. Since the differential diagnosis between precancerous dysplastic nodules and early HCC remains extremely difficult, we addressed the potential of FTIR microspectroscopy for grading cirrhotic nodules. The study was focused on 39 surgical specimens including normal livers as controls, dysplastic nodules, early HCC and the progressed HCC. Profound alterations of the biochemical composition of the pathological liver were demonstrated by FTIR microspectroscopy. Indeed, dramatic changes were observed in lipids, proteins and sugars highlighting the metabolic reprogramming in carcinogenesis. The major changes were observed in the frequency domain 950-1480 cm-1 in which several bands allowed significant discrimination of cirrhotic nodules, dysplastic lesions and HCC. Finally, a significant discrimination between benign, dysplastic nodules and early HCC remained possible using a FTIR microscope equipped with a laboratory-based infrared source that can be easily implemented in hospital environment. In conclusion, our study positions FTIR microspectroscopy as a versatile and powerful approach for investigating liver diseases, such as steatosis, dysplastic lesions and cancer. Further studies on larger series of patients as well as on biopsies will allow confirming the clinical reliability of such spectral signatures. Therefore, we anticipate that FTIR microspectroscopy will open new avenue in clinical diagnosis

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24

Neiser, Richard A. "Considerations in the design and operation of synchrotron radiation beamlines (including a discussion on the properties of synchrotron radiation." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/101246.

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The X-ray optics of synchrotron radiation beamlines are considered in this paper. The characteristics of synchrotron radiation which make it the premier source of light for studies in many regions of the electromagnetic spectrum are given. A chapter is devoted to the collimating, focusing and monochromating optics of two X-ray diffraction beamlines at the National Synchrotron Light Source. The beamlines are operated by the Naval Research Laboratory (NRL) and the Oak Ridge National Lab (ORNL). The major optical components of these beamlines are reviewed in regards to their function and their flexibility. A detailed analysis is performed on the NRL X-ray collimating mirror. The mirror is treated as an elastically bent beam. Deflection and slope error equations are developed which relate the shape of the bent mirror to its ideal surface. Visible light diffraction patterns collected from the mirror helped to establish operating conditions which provide good collimation. When the observed patterns are wed to the theoretical calculations, estimates of the average figure error are made. Finally, the effect of a highly collimated synchrotron beam on the reproducibility of the integrated intensities from polycrystalline materials is considered. The calculations show that except for the most fine grained materials, representative intensity measurements can only be made when the sample is permitted to move.
M.S.

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25

Bechtold, Alexander. "Eine integrierte RFQ-Driftröhrenkombination für ein Medizin-Synchrotron." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=970026048.

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26

Melero, García Emilio. "Fragmentation studies of small molecules using synchrotron radiation." Licentiate thesis, KTH, Physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1697.

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This thesis presents experimental data on the fragmentationof gas phase sulfur hexafluoride (SF6) and deutheromethane(CD4) molecules after their interaction with synchrotronradiation in the energy range of 70-200 eV. The data wasobtained using coincidence spectroscopy between energy resolvedelectrons and ions (EREICO).

Degradation of the molecular bond upon selective ionizationof different molecular orbitals has been studied by measuringionic fragments in coincidence with energy selected electrons.Besides the direct ionisation of the orbitals also the indirectprocess, in which the hole is created by the decay of a highlyenergetic core-excited state, was studied. The differencesdetected in the fragmentation after the direct and indirectionisation of a selected orbital can be related, in some cases,with the relaxation of the nuclei in the potential energysurface of the core excited state during its lifetime, thusproviding information on the neutral core excited state.

An experimental set-up capable of photon inducedfluorescence spectroscopy (PIFs) studies of core excitedmolecules in the visible range has been constructed. Thistechnique can yield complementary information to the EREICOdata about the energy distribution in the fragmentation sincethe internal energy of excited emitted fragments that decay inthe visible can be measured. It also allows the detection ofpossible neutral fragments.

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27

Bao, Zhuo. "Synchrotron Radiation Studies of Free and Adsorbed Molecules." Doctoral thesis, Uppsala University, Surface and Interface Science Division, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8610.

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This thesis contains two parts. The first part concerns the research work on free molecules using synchrotron-radiation-related techniques. Auger electron spectra of two free open-shell molecules, O₂ and NO, were studied experimentally and theoretically. Photoionization experimental technique with tunable synchrotron radiation source was used to induce core-level electron ionization and obtain the KVV normal Auger electron spectra. A quantitative assignment of O₂ normal Auger spectrum was obtained by applying ab initio CI calculations and LVI Auger line shape simulations including the bond length dependence of Auger transition rates. The photon energy dependence of normal Auger electron spectra was focused on with photon energies in the vicinities of core-ionization threshold energies. Consequently, the MAPCI (Molecular Auger Post Collision Interaction) theory was developed. Taking the near-threshold O₂ normal Auger spectrum as an example, the two extreme cases of MAPCI effect, “atomic-like PCI” and “molecular PCI”, were discovered and discussed. The effect of shape resonance on near-threshold molecular normal Auger spectrum was discussed taking NO near threshold normal Auger spectra as example.

The second part deals with research work on the chemisorption of small epoxy organic molecules, ethylene oxide, methyl oxirane, on Si (100) surfaces. Synchrotron radiation related techniques, UPS, XPS and NEXAFS, were applied. Based on the valence photoemission spectra, C 1s and Si 2p XPS spectra, the epoxy ring opening reactions of these molecules in chemisorption process were proved. Further tentative search for the surface-adsorbate CDAD effect was performed, and no evident circular dichroism was confirmed.

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28

Cardwell, David A. "Compton scattering with gamma-rays and synchrotron radiation." Thesis, University of Warwick, 1987. http://wrap.warwick.ac.uk/99433/.

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Directional Compton profile measurements of aluminium and chromium have been performed with 60 keV and 412 keV γ-radiation to assess the complementarity of the 241Am and 198Au spectrometer systems in common use by experimentalists. Revision of the data reduction procedure has yielded symmetrical Compton profiles within experimental error for the first time. The effects of exchange and correlation on theoretical Compton profiles calculated within the local density approximation have been evaluated via the Lam-Platzman correction and applied to existing transition metal results. Novel experiments using circularly polarised synchrotron radiation to detect the magnetic Compton profiles of iron and nickel have been performed successfully.

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29

Koscielniak, S. R. "Longitudinal beam dynamics studies on the ISIS synchrotron." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379845.

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Myles, Dean Aubrey Albert. "Synchrotron X-radiation studies of C-reactive proteins." Thesis, Keele University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305880.

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Miles, Andrew John. "Synchrotron radiation circular dichroism : standardisation and new methods." Thesis, Birkbeck (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428084.

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32

McCarthy, Joanne. "Magnetic Compton scattering with high energy synchrotron radiation." Thesis, University of Warwick, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263118.

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33

Innocenti, Fabrizio. "Photoelectron spectroscopy of reactive intermediates with synchrotron radiation." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417983.

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34

Mackenzie, Dover C. M. "Synchrotron studies of technologically important metal oxide surfaces." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1456184/.

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This thesis probes three technologically important metal-oxide systems; Pd nanoparticles supported on the TiO2(110) surface, acetate on TiO2(110) and Fe3O4(111). The orientation of CO adsorbed to a Pd/TiO2(110) model catalyst system was probed using X-ray photoemission electron microscopy (XPEEM) and near-edge X-ray absorption fine structure (NEXAFS). The absorbed CO molecules were found to have an off-normal polar orientation, relative to the basal plane of the substrate. The result was interpreted as an average of several sets of CO molecules absorbed and oriented orthogonally to various facets of the Pd nanoparticles, some of the facets themselves orientated with an angular separation from the basal plane. The acetate saturated TiO2(110) surface was examined using photoelectron spectroscopy (PES) and NEXAFS under UHV conditions as well as under increased pressures of acetic acid. The coverage and orientation of the adsorbed acetic acid were studied. It was found that a second 0.5 ML of acetate, additional to the half-monolayer film observed in UHV, develops under 0.01 Torr of acetic acid pressure. This second layer is thought to be hydrogen bonded to hydroxyl groups that are formed during the absorption of the first layer. Additionally, the 1st half-monolayer is shown to be slightly tilted, this is believed to be the effect of hydroxyls and to influence the tilt of the second layer. Structural characterisation work was carried out on the Fe3O4(111) single-crystal surface with low energy electron diffraction. Full characterisation was not possible due to incomplete experimental data, however, a novel version of the analysis software CLEED was developed to accommodate simultaneous mutliple domain analysis.

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Carnerero, Maria, Claudia Raiteri, Massimo Villata, Pulido Jose Acosta, Paul Smith, and Valeri Larionov. "Investigating the Puzzling Synchrotron Behaviour of Mrk 421." MDPI AG, 2016. http://hdl.handle.net/10150/622694.

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We investigate the multiwavelength behaviour of the high-energy peaked BL Lac object (HBL) Mrk 421 at redshift z = 0.031 in the period 2007-2015. We use optical photometric, spectroscopic, and polarimetric data and near-infrared data obtained by 35 observatories participating in the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), as well as by the Steward Observatory Support of the Fermi Mission. We also employ high-energy data from the Swift (UV and X-rays) satellite to study correlations among emission in different bands.

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36

Shilova, Anastasiia. "Development of serial protein crystallography with synchrotron radiation." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY034/document.

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Le rayonnement synchrotron est l'un des facteurs clés du grand succès de la cristallographie macromoléculaire au cours des dernières décennies. Plus de 90% de toutes les structures de protéines de la base de données PDB a été résolu par cristallographie en utilisant des sources de rayonnement synchrotron et environ 95% d'entre elles a été déterminé à partir de cristaux congelés.Cependant, les structures déterminées par des techniques de congélation sont limitées par la nature statique des cristaux congelés. Avec le développement récent des sources de RX produites par lasers à électrons libres (XFEL), qui sont en mesure de produire des impulsions femtosecondes très intenses de rayons X, l'ère de la « diffraction avant destruction » et de la cristallographie sérielle femtoseconde utilisant des micro- ou nano- cristaux a commencé (SFX).Au cours du procédé SFX un cristal de protéine n'est exposé qu'une fois au faisceau de rayons X pendant quelques dizaines de femtosecondes avant qu'il ne soit complètement détruit. Les données sont collectées à partir de cristaux orientés de façon aléatoire par rapport au faisceau de rayons X; une seule exposition par cristal est possible. Afin de recevoir un ensemble de données plus complet, de nouvelles techniques d'analyse de données de diffraction ont été développées.La première expérimentation réussie du procédé (SFX) a été réalisée au LCLS à Stanford en décembre 2009 sur des cristaux du photosystème I et de lysozyme. Les experts en cristallographie des installations XFEL peuvent déterminer des structures de protéines à température ambiante presque exemptes de dégâts d'irradiation, en raison des pulses de FEL femtosecondes si brèves, qu'ils passent à travers l'échantillon avant que des dommages de rayonnement importants ne se produisent.Après la présentation des premières expériences SFX réussies, des efforts pour effectuer une cristallographie en série de cristaux de taille de l’ordre des micromètres à température ambiante ont commencé au sein des synchrotrons. Une première tentative de cristallographie synchrotron en série et à température ambiante a été tentée à PETRA III à DESY à Hambourg. Cette méthode a été nommée SMX (synchrotron serial millisecond crystallography), où des milliers d'échantillons sont collectés à partir de cristaux individuels passant par le faisceau à rayons X. Avec le développement des techniques de cristallographie série à température ambiante au sein des synchrotrons, la répartition de la dose sur un grand nombre de cristaux compense l’augmentation des dommages liés à l’irradiation à température ambiante.Bien que les sources de rayonnement synchrotron n'atteindront probablement jamais la même luminosité que les impulsions de rayons X comme dans les XFELs, elles ont un certains nombre d'avantages. L'un d'eux est la flexibilité de configuration grâce au paramétrage de lignes de faisceaux microfocus. Un autre est que plusieurs expositions par cristal sont possibles. En outre, les synchrotrons sont plus répandus dans le monde: la probabilité d'obtenir un temps d'expérimentation dans un synchrotron est plus élevée que pour une installation XFEL. En effet, maintenant deux installations XFEL sont ouvertes pour les utilisateurs .L'objectif de cette thèse est de proposer et de mettre en œuvre des méthodes qui permettront de recueillir des données en utilisant l'approche de la cristallographie série à l'installation synchrotron européen (ESRF, Grenoble, France). Cette thèse présente différentes techniques pour réaliser la cristallographie sérielle sur la ligne ID13 à l’ESRF. L'objectif était de développer la cristallographie sérielle sur synchrotron basée sur la numérisation micro-diffraction pour démontrer que les sources de rayonnement synchrotron peuvent être utilisées comme un instrument de routine pour cette technique avec des protéines globulaires et membranaires. Les aspects de la collecte de données et leur traitement seront également discutés
Synchrotron radiation is one of the key factors for the tremendous success of macromolecular crystallography during the past decades. More than 90 % of all protein structures in PDB database were solved by crystallography using synchrotron radiation sources and around 95 % of them were determined from cryocooled crystals1,2. A whole data set can be collected from one flash-cooled crystal. Data-collection at cryogenic temperatures drastically reduces radiation damage effects. However, structures determined using cryo freezing techniques are limited by static nature of frozen crystals.With the recent development of X-ray free-electron laser facilities (XFELs), which are able to produce extremely intense femtosecond X-ray pulses, the era of “Diffraction before destruction” and serial femtosecond crystallography (SFX) for micro-/nano-sized crystals has begun3. In the SFX technique a protein crystal is only exposed once to the X-ray beam for tens of femtoseconds before it is completely destroyed. The data is collected from randomly oriented crystals that are exposed to the X-ray beam; only one shot per crystal is possible. In order to receive a complete data set, new data analysis techniques that are capable of dealing with large quantities of diffraction data have been developed. First experiment where serial femtosecond crystallography (SFX) approach was first carried out was performed at the Linac Coherent Light Source (LCLS, Stanford, USA) in December 2009 on photosystem I and lysozyme crystals4,5,6. At XFELs facilities crystallographers can perform room temperature structure determination of proteins almost free of radiation damage, due to the fact that femtosecond flashes of FEL is so brief, that it passes through the sample before the significant radiation damage occurs.After presenting first successful experiments with SFX technique, efforts to perform serial crystallography of micron-sized crystals at room-temperature started at synchrotron sources. First attempt to perform synchrotron room-temperature serial crystallography has been done at PETRA III at DESY in Hamburg using glass capillary based microfluidics7. This method was named synchrotron serial millisecond crystallography (SMX), where thousands of patterns are collected from individual crystals passing through the X-ray beam8. With development of room-temperature serial crystallography techniques at the synchrotrons, the exposure distributed on a large number of crystals in the sample, which helps compensating the effect of increased radiation damage at ambient temperature.Although synchrotron sources most certainly will never reach the same brightness of X-ray pulses like XFELs, they have some advantages. One of them is possibility to perform any set up due to the flexibility of the parameters of microfocus beamlines. Another advantage of SMX is that several shots per crystals are possible. Also should be mentioned that synchrotrons are more widespread all over the world, so possibility to get a beamtime at the synchrotron is much higher than at XFELs, because currently only two XFEL facilities are open for users (LCLS, USA and SACLA, Japan).The aim of this dissertation is to propose and to implement methods that will allow to collect data using the serial crystallography approach at the European synchrotron radiation facility (ESRF, Grenoble, France). This dissertation presents different techniques to perform synchrotron serial crystallography at ID13 beamline. The goal was to develop synchrotron serial crystallography based on scanning micro-diffraction to demonstrate that synchrotron sources can be used as a routine instrument to perform serial crystallography with soluble and membrane proteins. The aspects of the data collection and data processing also will be discussed

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37

Brunelle, Mathilde. "Study of Salt Aerosols At the Synchrotron Soleil." Thesis, Uppsala universitet, Molekyl- och kondenserade materiens fysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-355735.

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38

Eypper, Marie. "Photoionisation studies of reactive intermediates with synchrotron radiation." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/191337/.

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39

LIU, ZEWEN. "Lithographie profonde par rayons-x sur rayonnement synchrotron." Paris 11, 1997. http://www.theses.fr/1997PA112064.

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Cette these concerne la lithographie profonde par rayons-x dont le but est la fabrication de microstructures. En utilisant le rayonnement synchrotron (rs) dans le domaine spectral 1 - 5 angstrom, on peut transferer les motifs d'un masque dans une couche de resine epaisse (500 m). Les microstructures en resine (comme le polymethylmethacrylate, pmma) sont obtenues apres dissolution des parties irradiees dans un solvant organique. Cette methode permet de realiser des microstructures a haut facteur de forme (rapport hauteur sur largeur), de dimensions laterales minimales de l'ordre de quelques microns et de precision submicronique. L'etape suivante d'electrodeposition permet d'obtenir des microstructures metalliques (ni, ni-fe par exemple) ou un moule qui sera utilise pour la reproduction en grand nombre de microstructures en polymere, metal, l'ensemble de ces procedes est rassemble sous le terme liga (lithographie, electroformage, moulage). Nous avons etabli un modele de developpement pour resine epaisse ou, entre autres parametres, les attaques sur les parois des structures sont prises en compte. La vitesse de dissolution de la resine irradiee, qui varie avec la dose de rayons-x absorbee, peut etre deduite des courbes de distribution de dose et des mesures experimentales. En utilisant ces donnees, on peut simuler la forme des microstructures obtenues apres developpement. Les facteurs qui influent sur la precision du transfert des motifs sont la divergence de la source du rs, la diffraction, l'emission d'electrons, la dilatation thermique du masque et la parallaxe. Des microstructures avec des parois lisses et verticales peuvent etre realisees sur dci sous la condition que l'epaisseur d'absorbant du masque soit superieure a 15 m. Des microstructures en resine pmma ou metalliques comme des microengrenages, des detecteurs micropistes, des micropinces et des microlentilles ont ete realise

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40

Morris, Christopher. "Synchrotron powder diffraction studies of metal-organic frameworks." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41941/.

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This thesis describes a variety of high resolution synchrotron powder diffraction studies of guest-loaded metal-organic frameworks (MOFs). These studies have been used to provide insight into the binding mechanisms of the guest molecules. Chapter 1 contains an introduction to MOFs, highlighting some potential applications that were investigated in this work. A description of the powder diffraction analysis techniques is also included. Chapter 2 describes the design and implementation of a remote control gas dosing system for use on the powder diffraction beamline (I11) at Diamond Light Source. To assess the precision of this system, and to gain an insight into the high CO2/N2 selectivity of the V(III) MOF, MFM-300(V), an in situ powder diffraction experiment was performed, firstly using pure CO2 and then with an equimolar mixture of CO2/N2. Two CO2 sites were found in all cases, with CO2-A forming a dipole-dipole interaction with the framework’s hydroxyl group, and CO2-B interacting with CO2-A via further dipole-dipole interaction. In the presence of N2, particularly at low loadings, the positions of the CO2 molecules vary quite significantly due to the presence of disordered N2 within the pore. Further to this investigation, the long term SO2 adsorption stability of the Al(III) MOF, MFM-300(Al), was studied by powder diffraction. The SO2-loaded MOF was found to remain stable over a period of 37 weeks. In Chapter 3, an investigation into the C8 hydrocarbon vapour adsorption and liquid phase separation properties of MFM-300(M) (M=Al, V, In) is described, with supporting structural information obtained from high resolution powder diffraction. In the vapour phase, MFM-300(Al) was the only MOF of the three studied to show any discrimination between the 4 isomers, whereas in the liquid phase, it showed no significant separation. Conversely, MFM-300(In) showed the highest degree of separation of m-xylene from ethylbenzene and o-, and p-xylene, however this was accompanied by poor separation of ethylbenzene and o-xylene. MFM-300(V) showed a lesser degree of separation of m-xylene from ethylbenzene and o-, and pxylene, but with a much better separation of ethylbenzene and o-xylene. The structural studies revealed π-π stacking interactions between the C8 hydrocarbons and the phenyl ring of the framework, and in the case of MFM-300(In)(p-xylene), tetragonal I4122 → orthorhombic I212121 phase change was observed. To further investigate the apparent flexible nature of MFM-300(In), high pressure powder diffraction was used, and a similar phase change was observed at 0.584 GPa. Chapter 4 describes the synthesis and characterisation of a Zr(IV) MOF, MFM-450. The CO2 and N2 adsorption properties of this MOF were investigated, and it was found to adsorb 2.32 mmol/g CO2 at 273 K, followed by 1.97 mmol/g CO2 at 283 K, and 1.48 mmol/g CO2 at 298 K. The N2 adsorption at these temperatures was negligible, resulting in high selectivities. To investigate the nature of CO2 binding in MFM-450, in situ powder diffraction was used. Two CO2 adsorption sites were found. The site in cage A was found to interact with the phenyl ring of the framework via π-π interactions, and the site in cage B interacts with the carboxylate group of the phenyl ring via a dipole-dipole interaction.

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41

Eichelbaum, Maik. "Synchrotron- und laseraktiviertes Wachstum von Edelmetallpartikeln in Gläsern." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2008. http://dx.doi.org/10.18452/15747.

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Im Rahmen dieser Arbeit wurde die Methode der Synchrotronröntgenaktivierung entwickelt, um Edelmetallpartikel in Natron-Kalk-Silicatgläsern zu erzeugen. Diese Photoaktivierung ermöglichte es, den Nukleations- vom Wachstumsprozess der Metallteilchen zu trennen und somit sehr kleine Partikel und die Frühstadien des Wachstumsprozesses zu identifizieren. Die Gläser wurden mit Photolumineszenz-, UV-Vis-Absorptions-, EPR-, SAXS- sowie XANES-Spektroskopie untersucht. So konnten in synchrotronaktivierten Gold-dotierten Gläsern Golddimere nachgewiesen werden. Die thermische Behandlung bei 550°C führte über eine heterogene Nukleation zum Wachstum von Goldnanopartikeln. Als Modell für das Nukleationszentrum wurde das an eine Silanolateinheit gebundene Golddimer entwickelt. In synchrotronaktivierten Silber-dotierten Gläsern bildeten sich zunächst Silberatome. Während das Tempern bei 300°C zur Entstehung kleiner lumineszierender Silberteilchen führte, induzierte die thermische Behandlung bei 500°C das Wachstum von Silbernanopartikeln. Die Frühstadien des Gold- und Silberpartikelwachstums wurden als effiziente Donoren in Photolumineszenz-Energietransferprozessen identifiziert. Durch die Anwendung eines Sol-Gel-Spin-Coating-Verfahrens konnten Gold-dotierte Silicat-Titanat-Glasschichten mit einer Goldkonzentration von bis zu 20 mol% hergestellt werden. Die Goldnanopartikel, welche durch Tempern bei 300°C erzeugt wurden, waren durch eine dreiphotonisch induzierte nichtlineare Lumineszenz charakterisiert. Weiterhin konnte die Methode der Titan:Saphir-Laseraktivierung entwickelt und damit Goldnanopartikel-haltige, nanometergroße Strukturen in die Glasschichten geschrieben werden. TEM- und REM-Studien haben gezeigt, dass die Goldnanopartikel nicht nur in die Glasschicht eingebettet sind, sondern sich auch auf der Oberfläche befinden. Die Zugänglichkeit gegenüber Biomolekülen konnte durch den Nachweis der Oberflächen-verstärkten Ramanstreuung adsorbierter Adeninmoleküle bewiesen werden.
Within this work, the technique of synchrotron X-ray activation has been developed to generate noble metal particles in soda-lime silicate glasses. The photoactivation has enabled the separation of nucleation and growth of noble metal particles. Thus, very small particles and the early stages of the cluster growth process could be identified. The glasses have been characterized by photoluminescence, UV-Vis absorption, EPR, SAXS and XANES spectroscopy. As a result, gold dimers could be identified in synchrotron activated gold-doped glasses. Thermal annealing at 550°C has induced the growth of gold nanoparticles by heterogeneous nucleation. As a model for the nucleation center a gold dimer bound to a silanolate center has been suggested. In contrast to gold, in synchrotron activated silver-doped glasses non-luminescent silver atoms have been generated. Annealing at 300°C has induced the growth of small luminescent silver particles. After a thermal treatment at a higher temperature of 500°C silver nanoparticles have been generated. The early stages of the gold and silver cluster growth process have been identified as efficient donators in photoluminescence energy transfer processes. An unprecedented increase of the gold amount of up to 20 mol% has been achieved by the preparation of ultrathin silicate-titanate layers with a sol-gel spin-coating approach. The nonlinear photoluminescence of the gold nanoparticles generated by annealing at 300°C could be excited by a three-photon induced process. Furthermore, the technique of titanium:sapphire laser activation has been developed to write nanometer-sized patterns containing gold nanoparticles into the glassy layers. TEM and SEM studies have shown that the gold nanoparticles are not only embedded within the thin films, but are also located on top of the glassy layers. Their accessibility to biological molecules has been proven by determining the surface-enhanced Raman scattering of adsorbed adenine molecules.

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42

Hodgson, Torrance James Tate. "On the Search for the Synchrotron Cosmic Web." Thesis, Curtin University, 2022. http://hdl.handle.net/20.500.11937/89454.

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On the very largest of scales, the Universe is predicted to emit a faint radio signature as a result of ongoing structure formation: the so-called synchrotron cosmic web. This radio signature promises to shed light on vast, cluster-scale magnetic fields. In this work, we use both simulations to better understand the nature and distribution of this radio signal, and make several attempts towards practical detection using low frequency radio interferometers.

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Manfredda, M. "PROBING SYNCHROTRON RADIATION COHERENCE: THE HETERODYNE SPECKLE APPROACH." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/172631.

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In this manuscript we describe a novel method to map the two-dimensional transverse coherence of an x-ray beam using the dynamical near-field speckles formed by scattering from colloidal particles. The method is suitable for live beam diagnostics, allowing time-resolved measurements.

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Tong, Yongfeng. "Self-Assembly of Organic Molecules on Reactive Metal Substrates." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS522/document.

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Dans cette thèse, la formation de monocouches auto-assemblées de différentes molécules de chalcogénure et de molécules p-conjuguées planaire et leurs caractéristiques structurelles et électroniques ont été systématiquement étudiées principalement par spectroscopie photoélectronique à rayons X effectuée utilisant la lumière synchrotron, microscopie à effet tunnel à balayage et diffraction d'électrons à faible énergie. Une étude de la formation de structures hybrides organiques-inorganiques auto-assemblées a été réalisée par assemblage couche par couche d'un dithiol sur ZnO (0001) avec dépôt de métal intermédiaire. De plus en complément de l'étude des molécules comportant un atome de chalcogènure, les caractéristiques d'adsorption du sélénium et du soufre ont été étudiées. La spectroscopie XPS à haute résolution et la spectroscopie de structure fine d’absorption au seuil d’excitation (NEXAFS) ont permis d'étudier les caractéristiques des monocouches auto-assemblées du sélénure de benzène et du sélénophène sur Cu (100) et dihexyldiselénure sur Ni (111) et Pd (111) et ont montré en particulier l’existence de processus de rupture de liaison Se-C ainsi que l’existence de différents sites d'adsorption de molécules. Ces conclusions ont été soutenues par l'étude de l'adsorption atomique du sélénium, qui montre également l'existence de différents sites d'adsorption pour le Se atomique avec différents environnements chimiques. Ces conclusions sont principalement basées sur une étude XPS haute résolution des spectres caractéristiques Se3d, Se3p, du spectre de bande de valence et de l'imagerie LEED. La formation de monocouche de 5,5-bis (mercaptéthyl) -2,20-bipyridine (BPD) avec terminaison SH libre sur ZnO(0001) a été démontrée, permettant le greffage ultérieur d'Ag et Ni et de l’ assemblage d’une autre couche de BPD sur cette couche de métal-dithiol. Les changements dans les propriétés électroniques ont été déterminés à partir des spectres de la bande de valence. La molécule π-conjuguée, NTCDA, a été déposée sur différentes surfaces métalliques et sa morphologie structurelle et ses propriétés chimiques par rapport à la surface métallique ont été étudiées. Les molécules NTCDA affichent une structure « couchée » avec deux domaines différents sur Ag (110) et Cu (100) mais trois domaines sur la surface de Cu (111). Par rapport à celui sur la surface inerte de Au, une forte interaction entre les molécules et les substrats de Cu, Ag existe et joue un rôle important dans la détermination de l'orientation et de l'état de liaison des films organiques
In this thesis, the formation of self-assembled monolayers of different chalcogenide molecules and planer π-conjugated molecules and their electronic and structural characteristics were systematically studied mainly by synchrotron based X-ray photoelectron spectroscopy, scanning tunneling microscopy and low energy electron diffraction. A study of formation of hybrid organic-inorganic self assembled structure was performed by layer by layer assembly of a dithiol on ZnO(0001) with intermediate metal deposition. Additionally as a complement to the study of chalcogen head group molecules the adsorption characteristics of selenium and sulfur were investigated. The high resolution XPS and near edge absorption fine structure spectroscopy allowed to investigate the characteristics of self-assembled monolayers of benzene selenide and selenophene on Cu (100), and dihexyldiselenide on Ni(111) and Pd(111) and showed in particular the existence of Se-C bond breaking processes and existence of different adsorption sites of molecules. These conclusions were supported by the study of atomic selenium adsorption, which also shows existence different adsorption sites for the atomic Se with different chemical environments. These conclusions are mainly based on high resolution XPS study of characteristic Se3d, Se3p spectra, valance band spectrum and LEED imaging. The formation of a 5,5- bis (mercaptomethyl)-2,20- bipyridine (BPD) with SH termination on ZnO(0001) was demonstrated allowing subsequent grafting of Ag and Ni and further assembly of BPD on this metal-dithiol layer. The changes in electronic properties were determined from valence band spectra. The large π-conjugated molecule, NTCDA, was deposited on different metal surfaces and its structure morphology and chemical properties with respect to the metal surface was investigated. The NTCDA molecules displays a lying down structure with two different domains on Ag (110) and Cu(100) but three domain on Cu(111) surface. Compared with the one on the inert Au surface, a strong interface interaction between the molecules and Cu, Ag substrates plays an important role in determining the orientation and bonding state of the organic films

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Attal, Maher. "Lattice optimization and nonlinear beam dynamical studies on SESAME and SOLEIL storage rings." Paris 11, 2009. http://www.theses.fr/2009PA112095.

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Les méthodes employées pour optimiser les sources de rayonnement synchroton sont discutées et utilisées pour le design de la future maille de l’anneau de stockage de SESAME. La stratégie adoptée pour l’optimisation linéaire et non-linéaire a conduit à l’obtention de grandes ouvertures dynamiques, ce qui garantira théoriquement une bonne efficacité d’injection et une bonne duré de vie. Il a été aussi montré dans cette thèse l’importance et la nécessité d’inclure les dimensions de la chambre à vide dans les calculs de l’ouverture dynamique lors de l’optimisation non-linéaire de la maille de SESAME. En effet, des résonances destructives n’ont pu être mises en évidence lors du calcul de l’ouverture dynamique sans chambre à vide. Cette étude a été corroborée en utilisant de façon exhaustive l’analyse en fréquence (FMA). Une nouvelle méthode a été adoptée pour la réduction du premier ordre du momentum compaction factor (α1) tout en gardant une émittance faible. Cette technique a été appliquée théoriquement et expérimentalement avec succès sur l’anneau de stockage de SOLEIL. Le but étant d’obtenir des parquets très courts. Le rayonnement cohérent (CSR) provenant de la ligne IR, AILES, de SOLEIL a pu être observé pas loin du domaine du THz. Pendant l’une de ces expériences, trois faisceaux distincts ont pu être stockés de façon simultanée. C’est pour la première fois qu’une observation de ce type a pu être faite. Une analyse utilisant un développement théorique jusqu’au troisième ordre du momentum compaction factor a permis d’expliquer les conditions d’apparition de ces trois faisceaux. La dernière partie de cette thèse concerne l’installation, les tests de réhabilitation de l’ancien Microtron de BESSY 1 comme pré-injecteur pour la machine de SESAME
Some aspects in designing a lattice for synchrotron light sources have been discussed and used to design the future lattice for SESAME storage ring. The adopted strategy for the linear and nonlinear optimization resulted in large dynamic apertures which guarantees good injection efficiency and beam lifetime. It has been shown that including the vacuum chamber in the dynamic aperture calculations was a necessary tool in the nonlinear optimization of SESAME lattice since it was possible to see inner destructive nonlinearities wich couldn’t be seen in case of absolute dynamic aperture calculations. This idea has been supported by the Frequency Map Analysis (FMA) method. A new method has been adopted to reduce the first order momentum compaction factor (α1) keeping a low emittance. This technique has been applied to SOLEIL machine to have extremely short bunches theoretically and experimentally. The Coherent Synchrotron Radiation (CSR) from the infrared beam line AILES could be observed in the Tera Hertz region. During one of these experiments three beams have been stored simultaneously in the storage ring. It is, to our knowledge, the first observation of such event. A trial to explain this event is done by deriving analytical formulas to evaluate α1, α2 and α3 experimentally. An experience is shown in rehabilitating the old BESSY I Microtron in order to be used as a pre-injector for SESALME machine

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Rack, Alexander. "Untersuchung komplexer Materialsysteme mittels Synchrotron-Tomographie und 3D-Bildanalyse." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=981207448.

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Bessette, Daniel Robert. "Analyse und Quantifizierung geologischer Proben mit der Synchrotron-Röntgenfluoreszenz." [S.l. : s.n.], 1999. http://www.sub.uni-hamburg.de/disse/98/dissert.pdf.

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Álvarez, Ruiz Jesús. "Photon induced fluorescence studies of molecules using synchrotron radiation." Licentiate thesis, KTH, Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1567.

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This Licentiate thesis presents research accomplished at theSection of Atomic and Molecular Physics at the Royal Instituteof Technology in Stockholm using photon induced fluorescencespectroscopy (PIFS) during the last two years.

The main results presented are summarized:

- Neutral photodissociation in CO was observed aftersynchrotron photon excitation in the range 19-26 eV bycollecting dispersed fluorescence from excited neutral C atoms.Follow-up ab initio calculations point out CO Rydberg seriesconverging to the CO+ C and D states as precursors.

- The branching ratio between N2 + (B-X)(v=1,v=2) and (v=0,v=1)transitions in the 20-46 eV energy range reveals strongnon-Franck-Condon effects. Ab initio calculations indicate thatthe autoionization of certain superexcited states areresponsible for some of the structures present in the branchingratio curve, confirming the important role of non-Rydbergdoubly excited resonant states (NRDERS) in de-excitationprocesses above the ionization potential.

- Photon induced neutral dissociation processes in NO arereported. Neither Rydberg series nor other molecular states inNO known so far can account for the collected data. From abinitio calculations more information regarding the NO precursorstates and the mechanism behind the observed neutraldissociation were obtained.

- The details of a new experimental set-up for gas phasefluorescence measurements using synchrotron radiation aredescribed. It is able to perform simultaneous measurements ofdispersed and total fluorescence in the visible range. Thefirst results obtained with this set-up are presented,concerning fluorescence after excitation of the N2 molecules inthe N 1s edge.

These four studies conform the set of papers enclosed in theLicentiate thesis.

Finally a pre-study to further apply PIFS to speciespreviously excited by microwave discharge is included as futureplans.

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Rius, i. Riu Jaume. "Gas phase molecular relaxation probed by synchrotron radiation experiments." Doctoral thesis, KTH, Physics, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3411.

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This thesis presents experimental studies of gas phasemolecular relaxation after excitation with synchrotron photonsin the 15-35 eV and in the 70-350 eV regions.

In the 15-35 eV region, molecular relaxation by neutraldissociation processes and non

Franck-Condon effects in N2 and O2 molecules have beenstudied by means of dispersed fluorescence and photoelectronspectroscopy experimental techniques, respectively. From thedispersed fluorescence data, excitation functions for themeasured atomic fluorescence spectra have been obtained. Fromthe recorded photoelectron spectra vibrational branching ratioshave been produced. The results obtained reveal that Rydbergseries and singly and doubly excited valence states of theappropriate symmetry energetically accessible in the studiedregion and interactions between themaccount for most of theobserved effects in these two type of experiments.

In the 70-350 eV range, molecular relaxation processesresulting in fragmentation of CD4 and SF6 after absorption ofsynchrotron light have been studied by energy resolved electronion coincidence technique using a multicoincidence experimentalstation developed by our group during the last five years forsuch type of experiments. The coincidence measurements yieldedmass spectra from which information about the kinematics of thedetected fragments has been deduced by means of Monte Carlosimulations of the experimental peak shapes. The obtainedresults show completely different dissociation patternsdepending on the molecular electronic states studied. Thesepatterns reflect the bonding properties of the excited orbitalsand they permit the description and in some cases theidentification of the different molecular relaxation pathwaysobserved. The achievements presented in this thesis exemplifythe potential of the multicoincidence station used in thereported experiments.

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Vall-Llosera, Gemma. "Flourescence properties of trendy molecules studied with synchrotron radiation." Licentiate thesis, KTH, Physics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4148.

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This thesis summarises the experimental results on molecular spectroscopy of gas phase molecules using synchrotron radiation in the UV- VUV and soft-X rays regions. The results of applying Photon Induced Fluorescence Spectroscopy (PIFS) to D2, H2S, H2O and pyrimidine are presented and discussed. Both inner and outer shell excitations of free molecules lead to different relaxation processes. However, a common result is that when the molecule breaks and the resulting neutral fragments are left in an excited state, they might fluoresce in the UV- Vis range. PIFS technique has two main advantages, it permits to detect neutral fragments and to identify the fluorescing species. From this fact, we can infer dissociation channels and trace back the electronic processes that led to the fluorescence. For these molecules we have analysed and interpreted both dispersed and undispersed fluorescence. What motivates our work is the lack of fluorescence studies and in a more general sense, to contribute to the knowledge of important molecules for life such as water and pyrimidine.

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Dissertations / Theses on the topic 'Synchrotron'

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